High-throughput screening (HTS) of small-molecule libraries and Natural product extracts is a crucial component of modern-day drug discovery. Popular HTS methods rely largely on fluorescence and FRET-based sensing protocols, which are fraught with inherent limitations, which include high cost and incompatibility with certain species. Given that an overwhelming majority of drugs candidates are identified through HTS efforts, the long-term goal of this research program is the development of better sensing methods that can quickly identify lead therapeutics under physiologically relevant conditions. The objective of this subproject is the establishment of powerful new platforms and methods that can detect biomolecule binding phenomena. These systems will help map new biological signaling pathways, and identify small-molecule chemical probes and therapeutic leads. Based on our initial work and expertise in this area, we have identified the following specific aims for this program: (1) Development of ECL-based Electrode Microarrays for Therapeutic Lead Discovery; and (2) Development of ECL-based Electrode Microarrays for Label-Free Biomolecule Detection and Protein Panning. Both of these endeavors are innovative as they will permit protein binding interactions to be probed under a broad array of conditions, using compounds that are often incompatible with modern HTS methods. The proposed research is significant because it will establish new sensing paradigms for protein binding phenomena, provide general and robust platforms to screen small-molecule antagonists, and enable protein-panning experiments to be pursued. Further, by functioning as an essential cog within a collaborative network, this subproject will not only help define new protein targets for therapeutic development, but also provide the means to identify hit compounds that can be advanced into new chemical probes.